title: Anticoagulation duration in heterozygous factor V Leiden: a decision analysis.
abstract: BACKGROUND
  Current anticoagulation guidelines suggest that optimal anticoagulation duration for unprovoked venous thromboembolism is determined by an individual risk assessment, balancing risks of anticoagulation bleeding with venous thromboembolism recurrence. Among individuals heterozygous for the factor V Leiden mutation, while venous thromboembolism recurrence risk is greater, the risk for bleeding is recognized to be lower, suggesting longer duration anticoagulation could be considered.
  
  
  OBJECTIVE
  The objective of this study was to compare standard vs. lifelong anticoagulation in 20-year-old factor V Leiden heterozygotes with unprovoked venous thromboembolism.
  
  
  METHODS
  A Markov state-transition model was used, incorporating risks of major, minor, and fatal anticoagulation bleeding, bleeding and thromboembolism morbidity and mortality, and quality of life utilities. Model parameter values favoring lifelong anticoagulation in factor V Leiden heterozygotes were determined in sensitivity analyses. Outcomes were in quality-adjusted life years, discounted at 3% per year.
  
  
  RESULTS
  In general population groups with odds ratios for venous thromboembolism recurrence and anticoagulation bleeding of 1.0, a short-term anticoagulation strategy gained 0.09 quality-adjusted life years more than a lifelong anticoagulation strategy. By contrast, in factor V Leiden heterozygotes, lifetime anticoagulation was favored if their relative risk of venous thromboembolism was greater than 1.07 or their relative risk for bleeding was less than 0.91. Results were relatively insensitive to individual variation in other parameter values.
  
  
  CONCLUSIONS
  Lifelong anticoagulation may benefit individuals heterozygous for factor V Leiden and previous idiopathic venous thromboembolism. Studies assessing bleeding risk with anticoagulation in factor V Leiden heterozygotes and the costs of indefinite anticoagulation are needed to determine if lifelong anticoagulation is the optimal strategy.
authors.affiliation: Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Donovan
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Smith
authors.forename: Margaret V
authors.initials: MV
authors.lastname: Ragni
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D003661:Decision Support Techniques; D004334:Drug Administration Schedule; D005165:Factor V / Q000235:genetics / Q000378:metabolism*; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D008390:Markov Chains; D011788:Quality of Life; D018570:Risk Assessment; D054556:Venous Thromboembolism / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism*
chemical_list: D000925:Anticoagulants; C095381:factor V Leiden; D005165:Factor V